The US Food and Drug Administration (FDA) has approved X4 Pharmaceuticals‘ XOLREMDI (mavorixafor) capsules for patients aged 12 and above with warts, hypogammaglobulinemia, infections and myelokathexis (WHIM) syndrome.

This marks a significant advancement in the treatment of WHIM syndrome, a rare combined primary immunodeficiency and chronic neutropenic disorder.

XOLREMDI is a selective CXC chemokine receptor 4 (CXCR4) antagonist. It is the first drug specifically indicated to treat patients with WHIM syndrome.

X4 Pharmaceuticals president and CEO Paula Ragan stated: “The approval of XOLREMDI is a transformational milestone both for X4 and, more importantly, for the WHIM syndrome community.

“We are incredibly grateful to the people living with WHIM syndrome, their families, and the investigators who took part in our clinical programme, to US regulators for their continued focus on rare-disease treatment development, and to our dedicated employees for making this targeted breakthrough therapy a reality.”

The approval follows a priority review of data from the 4WHIM Phase III clinical trial, demonstrating the drug’s efficacy in increasing mature neutrophils and lymphocytes in the bloodstream.

The pivotal Phase III study included 31 participants diagnosed with WHIM syndrome and assessed the safety and efficacy of XOLREMDI over 52 weeks.

This drug showed significant improvement in absolute neutrophil counts and lymphocyte counts and reduced infections.

X4 Pharmaceuticals also obtained a rare paediatric disease priority review voucher, which can be used for future applications or sold to other drug sponsors.

In the US, X4 plans the commercial launch of XOLREMDI through its speciality pharmacy partner, PANTHERx Rare.

The Immune Deficiency Foundation’s president and CEO Jorey Berry stated: “Effective and innovative treatments are critical for those diagnosed with primary immunodeficiency. The approval of XOLREMDI marks an important advancement for people living with WHIM syndrome, who are susceptible to serious and frequent infections.

“We are very pleased to have been a partner to X4 in their journey to bring this much-needed treatment to this underserved rare disease community.”